Commit | Line | Data |
---|---|---|
9b27105b SB |
1 | /* |
2 | * Copyright (C) ST-Ericsson AB 2010 | |
26ee65e6 | 3 | * Author: Sjur Brendeland |
9b27105b SB |
4 | * License terms: GNU General Public License (GPL) version 2 |
5 | */ | |
6 | ||
a6b7a407 | 7 | #include <linux/hardirq.h> |
9b27105b | 8 | #include <linux/init.h> |
9b27105b SB |
9 | #include <linux/module.h> |
10 | #include <linux/device.h> | |
11 | #include <linux/types.h> | |
12 | #include <linux/skbuff.h> | |
13 | #include <linux/netdevice.h> | |
14 | #include <linux/rtnetlink.h> | |
15 | #include <linux/tty.h> | |
16 | #include <linux/file.h> | |
17 | #include <linux/if_arp.h> | |
18 | #include <net/caif/caif_device.h> | |
19 | #include <net/caif/cfcnfg.h> | |
20 | #include <linux/err.h> | |
21 | #include <linux/debugfs.h> | |
22 | ||
23 | MODULE_LICENSE("GPL"); | |
26ee65e6 | 24 | MODULE_AUTHOR("Sjur Brendeland"); |
9b27105b SB |
25 | MODULE_DESCRIPTION("CAIF serial device TTY line discipline"); |
26 | MODULE_LICENSE("GPL"); | |
27 | MODULE_ALIAS_LDISC(N_CAIF); | |
28 | ||
29 | #define SEND_QUEUE_LOW 10 | |
30 | #define SEND_QUEUE_HIGH 100 | |
31 | #define CAIF_SENDING 1 /* Bit 1 = 0x02*/ | |
32 | #define CAIF_FLOW_OFF_SENT 4 /* Bit 4 = 0x10 */ | |
33 | #define MAX_WRITE_CHUNK 4096 | |
34 | #define ON 1 | |
35 | #define OFF 0 | |
36 | #define CAIF_MAX_MTU 4096 | |
37 | ||
56e0ef52 | 38 | static DEFINE_SPINLOCK(ser_lock); |
9b27105b | 39 | static LIST_HEAD(ser_list); |
56e0ef52 | 40 | static LIST_HEAD(ser_release_list); |
9b27105b | 41 | |
eb939922 | 42 | static bool ser_loop; |
9b27105b SB |
43 | module_param(ser_loop, bool, S_IRUGO); |
44 | MODULE_PARM_DESC(ser_loop, "Run in simulated loopback mode."); | |
45 | ||
eb939922 | 46 | static bool ser_use_stx = true; |
9b27105b SB |
47 | module_param(ser_use_stx, bool, S_IRUGO); |
48 | MODULE_PARM_DESC(ser_use_stx, "STX enabled or not."); | |
49 | ||
eb939922 | 50 | static bool ser_use_fcs = true; |
9b27105b SB |
51 | |
52 | module_param(ser_use_fcs, bool, S_IRUGO); | |
53 | MODULE_PARM_DESC(ser_use_fcs, "FCS enabled or not."); | |
54 | ||
55 | static int ser_write_chunk = MAX_WRITE_CHUNK; | |
56 | module_param(ser_write_chunk, int, S_IRUGO); | |
57 | ||
58 | MODULE_PARM_DESC(ser_write_chunk, "Maximum size of data written to UART."); | |
59 | ||
60 | static struct dentry *debugfsdir; | |
61 | ||
62 | static int caif_net_open(struct net_device *dev); | |
63 | static int caif_net_close(struct net_device *dev); | |
64 | ||
65 | struct ser_device { | |
66 | struct caif_dev_common common; | |
67 | struct list_head node; | |
68 | struct net_device *dev; | |
69 | struct sk_buff_head head; | |
70 | struct tty_struct *tty; | |
71 | bool tx_started; | |
72 | unsigned long state; | |
73 | char *tty_name; | |
74 | #ifdef CONFIG_DEBUG_FS | |
75 | struct dentry *debugfs_tty_dir; | |
76 | struct debugfs_blob_wrapper tx_blob; | |
77 | struct debugfs_blob_wrapper rx_blob; | |
78 | u8 rx_data[128]; | |
79 | u8 tx_data[128]; | |
80 | u8 tty_status; | |
81 | ||
82 | #endif | |
83 | }; | |
84 | ||
85 | static void caifdev_setup(struct net_device *dev); | |
86 | static void ldisc_tx_wakeup(struct tty_struct *tty); | |
87 | #ifdef CONFIG_DEBUG_FS | |
88 | static inline void update_tty_status(struct ser_device *ser) | |
89 | { | |
90 | ser->tty_status = | |
91 | ser->tty->stopped << 5 | | |
9b27105b SB |
92 | ser->tty->flow_stopped << 3 | |
93 | ser->tty->packet << 2 | | |
0d3b88d1 | 94 | ser->tty->port->low_latency << 1; |
9b27105b SB |
95 | } |
96 | static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty) | |
97 | { | |
98 | ser->debugfs_tty_dir = | |
99 | debugfs_create_dir(tty->name, debugfsdir); | |
100 | if (!IS_ERR(ser->debugfs_tty_dir)) { | |
101 | debugfs_create_blob("last_tx_msg", S_IRUSR, | |
102 | ser->debugfs_tty_dir, | |
103 | &ser->tx_blob); | |
104 | ||
105 | debugfs_create_blob("last_rx_msg", S_IRUSR, | |
106 | ser->debugfs_tty_dir, | |
107 | &ser->rx_blob); | |
108 | ||
109 | debugfs_create_x32("ser_state", S_IRUSR, | |
110 | ser->debugfs_tty_dir, | |
111 | (u32 *)&ser->state); | |
112 | ||
113 | debugfs_create_x8("tty_status", S_IRUSR, | |
114 | ser->debugfs_tty_dir, | |
115 | &ser->tty_status); | |
116 | ||
117 | } | |
118 | ser->tx_blob.data = ser->tx_data; | |
119 | ser->tx_blob.size = 0; | |
120 | ser->rx_blob.data = ser->rx_data; | |
121 | ser->rx_blob.size = 0; | |
122 | } | |
123 | ||
124 | static inline void debugfs_deinit(struct ser_device *ser) | |
125 | { | |
126 | debugfs_remove_recursive(ser->debugfs_tty_dir); | |
127 | } | |
128 | ||
129 | static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size) | |
130 | { | |
131 | if (size > sizeof(ser->rx_data)) | |
132 | size = sizeof(ser->rx_data); | |
133 | memcpy(ser->rx_data, data, size); | |
134 | ser->rx_blob.data = ser->rx_data; | |
135 | ser->rx_blob.size = size; | |
136 | } | |
137 | ||
138 | static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size) | |
139 | { | |
140 | if (size > sizeof(ser->tx_data)) | |
141 | size = sizeof(ser->tx_data); | |
142 | memcpy(ser->tx_data, data, size); | |
143 | ser->tx_blob.data = ser->tx_data; | |
144 | ser->tx_blob.size = size; | |
145 | } | |
146 | #else | |
147 | static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty) | |
148 | { | |
149 | } | |
150 | ||
151 | static inline void debugfs_deinit(struct ser_device *ser) | |
152 | { | |
153 | } | |
154 | ||
155 | static inline void update_tty_status(struct ser_device *ser) | |
156 | { | |
157 | } | |
158 | ||
159 | static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size) | |
160 | { | |
161 | } | |
162 | ||
163 | static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size) | |
164 | { | |
165 | } | |
166 | ||
167 | #endif | |
168 | ||
55db4c64 LT |
169 | static void ldisc_receive(struct tty_struct *tty, const u8 *data, |
170 | char *flags, int count) | |
9b27105b SB |
171 | { |
172 | struct sk_buff *skb = NULL; | |
173 | struct ser_device *ser; | |
174 | int ret; | |
175 | u8 *p; | |
c1f8fc57 | 176 | |
9b27105b SB |
177 | ser = tty->disc_data; |
178 | ||
179 | /* | |
180 | * NOTE: flags may contain information about break or overrun. | |
181 | * This is not yet handled. | |
182 | */ | |
183 | ||
184 | ||
185 | /* | |
186 | * Workaround for garbage at start of transmission, | |
187 | * only enable if STX handling is not enabled. | |
188 | */ | |
189 | if (!ser->common.use_stx && !ser->tx_started) { | |
190 | dev_info(&ser->dev->dev, | |
191 | "Bytes received before initial transmission -" | |
192 | "bytes discarded.\n"); | |
193 | return; | |
194 | } | |
195 | ||
196 | BUG_ON(ser->dev == NULL); | |
197 | ||
198 | /* Get a suitable caif packet and copy in data. */ | |
199 | skb = netdev_alloc_skb(ser->dev, count+1); | |
d3f744e0 SB |
200 | if (skb == NULL) |
201 | return; | |
9b27105b SB |
202 | p = skb_put(skb, count); |
203 | memcpy(p, data, count); | |
204 | ||
205 | skb->protocol = htons(ETH_P_CAIF); | |
206 | skb_reset_mac_header(skb); | |
9b27105b SB |
207 | debugfs_rx(ser, data, count); |
208 | /* Push received packet up the stack. */ | |
209 | ret = netif_rx_ni(skb); | |
210 | if (!ret) { | |
211 | ser->dev->stats.rx_packets++; | |
212 | ser->dev->stats.rx_bytes += count; | |
213 | } else | |
214 | ++ser->dev->stats.rx_dropped; | |
215 | update_tty_status(ser); | |
216 | } | |
217 | ||
218 | static int handle_tx(struct ser_device *ser) | |
219 | { | |
220 | struct tty_struct *tty; | |
221 | struct sk_buff *skb; | |
222 | int tty_wr, len, room; | |
c1f8fc57 | 223 | |
9b27105b SB |
224 | tty = ser->tty; |
225 | ser->tx_started = true; | |
226 | ||
227 | /* Enter critical section */ | |
228 | if (test_and_set_bit(CAIF_SENDING, &ser->state)) | |
229 | return 0; | |
230 | ||
231 | /* skb_peek is safe because handle_tx is called after skb_queue_tail */ | |
232 | while ((skb = skb_peek(&ser->head)) != NULL) { | |
233 | ||
234 | /* Make sure you don't write too much */ | |
235 | len = skb->len; | |
236 | room = tty_write_room(tty); | |
237 | if (!room) | |
238 | break; | |
239 | if (room > ser_write_chunk) | |
240 | room = ser_write_chunk; | |
241 | if (len > room) | |
242 | len = room; | |
243 | ||
244 | /* Write to tty or loopback */ | |
245 | if (!ser_loop) { | |
246 | tty_wr = tty->ops->write(tty, skb->data, len); | |
247 | update_tty_status(ser); | |
248 | } else { | |
249 | tty_wr = len; | |
250 | ldisc_receive(tty, skb->data, NULL, len); | |
251 | } | |
252 | ser->dev->stats.tx_packets++; | |
253 | ser->dev->stats.tx_bytes += tty_wr; | |
254 | ||
255 | /* Error on TTY ?! */ | |
256 | if (tty_wr < 0) | |
257 | goto error; | |
258 | /* Reduce buffer written, and discard if empty */ | |
259 | skb_pull(skb, tty_wr); | |
260 | if (skb->len == 0) { | |
261 | struct sk_buff *tmp = skb_dequeue(&ser->head); | |
f84ea779 | 262 | WARN_ON(tmp != skb); |
9b27105b SB |
263 | if (in_interrupt()) |
264 | dev_kfree_skb_irq(skb); | |
265 | else | |
266 | kfree_skb(skb); | |
267 | } | |
268 | } | |
269 | /* Send flow off if queue is empty */ | |
270 | if (ser->head.qlen <= SEND_QUEUE_LOW && | |
271 | test_and_clear_bit(CAIF_FLOW_OFF_SENT, &ser->state) && | |
272 | ser->common.flowctrl != NULL) | |
273 | ser->common.flowctrl(ser->dev, ON); | |
274 | clear_bit(CAIF_SENDING, &ser->state); | |
275 | return 0; | |
276 | error: | |
277 | clear_bit(CAIF_SENDING, &ser->state); | |
278 | return tty_wr; | |
279 | } | |
280 | ||
281 | static int caif_xmit(struct sk_buff *skb, struct net_device *dev) | |
282 | { | |
283 | struct ser_device *ser; | |
c1f8fc57 | 284 | |
9b27105b SB |
285 | BUG_ON(dev == NULL); |
286 | ser = netdev_priv(dev); | |
287 | ||
288 | /* Send flow off once, on high water mark */ | |
289 | if (ser->head.qlen > SEND_QUEUE_HIGH && | |
290 | !test_and_set_bit(CAIF_FLOW_OFF_SENT, &ser->state) && | |
291 | ser->common.flowctrl != NULL) | |
292 | ||
293 | ser->common.flowctrl(ser->dev, OFF); | |
294 | ||
295 | skb_queue_tail(&ser->head, skb); | |
296 | return handle_tx(ser); | |
297 | } | |
298 | ||
299 | ||
300 | static void ldisc_tx_wakeup(struct tty_struct *tty) | |
301 | { | |
302 | struct ser_device *ser; | |
c1f8fc57 | 303 | |
9b27105b SB |
304 | ser = tty->disc_data; |
305 | BUG_ON(ser == NULL); | |
f84ea779 | 306 | WARN_ON(ser->tty != tty); |
9b27105b SB |
307 | handle_tx(ser); |
308 | } | |
309 | ||
310 | ||
56e0ef52 KK |
311 | static void ser_release(struct work_struct *work) |
312 | { | |
313 | struct list_head list; | |
314 | struct ser_device *ser, *tmp; | |
315 | ||
316 | spin_lock(&ser_lock); | |
317 | list_replace_init(&ser_release_list, &list); | |
318 | spin_unlock(&ser_lock); | |
319 | ||
320 | if (!list_empty(&list)) { | |
321 | rtnl_lock(); | |
322 | list_for_each_entry_safe(ser, tmp, &list, node) { | |
323 | dev_close(ser->dev); | |
324 | unregister_netdevice(ser->dev); | |
325 | debugfs_deinit(ser); | |
326 | } | |
327 | rtnl_unlock(); | |
328 | } | |
329 | } | |
330 | ||
331 | static DECLARE_WORK(ser_release_work, ser_release); | |
332 | ||
9b27105b SB |
333 | static int ldisc_open(struct tty_struct *tty) |
334 | { | |
335 | struct ser_device *ser; | |
336 | struct net_device *dev; | |
337 | char name[64]; | |
338 | int result; | |
339 | ||
c93f0940 AC |
340 | /* No write no play */ |
341 | if (tty->ops->write == NULL) | |
342 | return -EOPNOTSUPP; | |
d3f744e0 SB |
343 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_TTY_CONFIG)) |
344 | return -EPERM; | |
c93f0940 | 345 | |
56e0ef52 KK |
346 | /* release devices to avoid name collision */ |
347 | ser_release(NULL); | |
348 | ||
cab6ce9e DC |
349 | result = snprintf(name, sizeof(name), "cf%s", tty->name); |
350 | if (result >= IFNAMSIZ) | |
351 | return -EINVAL; | |
9b27105b | 352 | dev = alloc_netdev(sizeof(*ser), name, caifdev_setup); |
c66b9b7d AC |
353 | if (!dev) |
354 | return -ENOMEM; | |
355 | ||
9b27105b | 356 | ser = netdev_priv(dev); |
e31d5a05 | 357 | ser->tty = tty_kref_get(tty); |
9b27105b SB |
358 | ser->dev = dev; |
359 | debugfs_init(ser, tty); | |
360 | tty->receive_room = N_TTY_BUF_SIZE; | |
361 | tty->disc_data = ser; | |
362 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
363 | rtnl_lock(); | |
364 | result = register_netdevice(dev); | |
365 | if (result) { | |
366 | rtnl_unlock(); | |
367 | free_netdev(dev); | |
368 | return -ENODEV; | |
369 | } | |
370 | ||
56e0ef52 | 371 | spin_lock(&ser_lock); |
9b27105b | 372 | list_add(&ser->node, &ser_list); |
56e0ef52 | 373 | spin_unlock(&ser_lock); |
9b27105b SB |
374 | rtnl_unlock(); |
375 | netif_stop_queue(dev); | |
376 | update_tty_status(ser); | |
377 | return 0; | |
378 | } | |
379 | ||
380 | static void ldisc_close(struct tty_struct *tty) | |
381 | { | |
382 | struct ser_device *ser = tty->disc_data; | |
c1f8fc57 | 383 | |
e31d5a05 | 384 | tty_kref_put(ser->tty); |
56e0ef52 KK |
385 | |
386 | spin_lock(&ser_lock); | |
387 | list_move(&ser->node, &ser_release_list); | |
388 | spin_unlock(&ser_lock); | |
389 | schedule_work(&ser_release_work); | |
9b27105b SB |
390 | } |
391 | ||
392 | /* The line discipline structure. */ | |
393 | static struct tty_ldisc_ops caif_ldisc = { | |
394 | .owner = THIS_MODULE, | |
395 | .magic = TTY_LDISC_MAGIC, | |
396 | .name = "n_caif", | |
397 | .open = ldisc_open, | |
398 | .close = ldisc_close, | |
399 | .receive_buf = ldisc_receive, | |
400 | .write_wakeup = ldisc_tx_wakeup | |
401 | }; | |
402 | ||
403 | static int register_ldisc(void) | |
404 | { | |
405 | int result; | |
c1f8fc57 | 406 | |
9b27105b SB |
407 | result = tty_register_ldisc(N_CAIF, &caif_ldisc); |
408 | if (result < 0) { | |
409 | pr_err("cannot register CAIF ldisc=%d err=%d\n", N_CAIF, | |
410 | result); | |
411 | return result; | |
412 | } | |
413 | return result; | |
414 | } | |
415 | static const struct net_device_ops netdev_ops = { | |
416 | .ndo_open = caif_net_open, | |
417 | .ndo_stop = caif_net_close, | |
418 | .ndo_start_xmit = caif_xmit | |
419 | }; | |
420 | ||
421 | static void caifdev_setup(struct net_device *dev) | |
422 | { | |
423 | struct ser_device *serdev = netdev_priv(dev); | |
c1f8fc57 | 424 | |
9b27105b SB |
425 | dev->features = 0; |
426 | dev->netdev_ops = &netdev_ops; | |
427 | dev->type = ARPHRD_CAIF; | |
428 | dev->flags = IFF_POINTOPOINT | IFF_NOARP; | |
429 | dev->mtu = CAIF_MAX_MTU; | |
9b27105b SB |
430 | dev->tx_queue_len = 0; |
431 | dev->destructor = free_netdev; | |
432 | skb_queue_head_init(&serdev->head); | |
433 | serdev->common.link_select = CAIF_LINK_LOW_LATENCY; | |
434 | serdev->common.use_frag = true; | |
435 | serdev->common.use_stx = ser_use_stx; | |
436 | serdev->common.use_fcs = ser_use_fcs; | |
437 | serdev->dev = dev; | |
438 | } | |
439 | ||
440 | ||
441 | static int caif_net_open(struct net_device *dev) | |
442 | { | |
9b27105b SB |
443 | netif_wake_queue(dev); |
444 | return 0; | |
445 | } | |
446 | ||
447 | static int caif_net_close(struct net_device *dev) | |
448 | { | |
449 | netif_stop_queue(dev); | |
450 | return 0; | |
451 | } | |
452 | ||
453 | static int __init caif_ser_init(void) | |
454 | { | |
455 | int ret; | |
c1f8fc57 | 456 | |
9b27105b SB |
457 | ret = register_ldisc(); |
458 | debugfsdir = debugfs_create_dir("caif_serial", NULL); | |
459 | return ret; | |
460 | } | |
461 | ||
462 | static void __exit caif_ser_exit(void) | |
463 | { | |
56e0ef52 KK |
464 | spin_lock(&ser_lock); |
465 | list_splice(&ser_list, &ser_release_list); | |
466 | spin_unlock(&ser_lock); | |
467 | ser_release(NULL); | |
468 | cancel_work_sync(&ser_release_work); | |
9b27105b SB |
469 | tty_unregister_ldisc(N_CAIF); |
470 | debugfs_remove_recursive(debugfsdir); | |
471 | } | |
472 | ||
473 | module_init(caif_ser_init); | |
474 | module_exit(caif_ser_exit); |